lll-V integration in Si and Ge by ion beam synthesis and flash lamp annealing

In order to follow Moore’s law on the path to smaller and smaller devices, more and more materials have to be integrated into Si technology. Current research activities focus on the integration of Ge and binary III-V compounds into Si, as these materials promise a further transistor performance increase due to their high hole and electron mobility, respectively. In addition, the direct band gap of most of the compound semiconductors is of great interest for optoelectronic applications. However, the integration into Si generates a lot of challenges regarding both the quality of the III-V material itself and the quality of its interfaces. At present, most integration technologies rely on molecular beam epitaxy or similar growth mechanisms. Recently, we showed that III-V nanocrystals (NC) in Si can also be fabricated by sequential ion implantation followed by flash lamp annealing (FLA) [1]. Moreover, the use of a patterned implantation mask allows the fabrication of III-V NCs in a Si nanowire at defined positions [2].

In this presentation we extend our previous investigations to the case of Ge. In order to get a better understanding of the NC formation process, InAs and GaAs NCs were fabricated in Si and Ge by ion implantation and FLA, and their structural and electric properties were compared to each other. It will be shown that the recrystallization of the near-surface layer of amorphous substrate material (Si or Ge), together with the NC formation, is rather governed by liquid phase than by solid phase epitaxy. This scenario is supported by the evaluation of the corresponding segregation and diffusion coefficients, the temperature profile during FLA and the final size distribution of the NCs.

[1] S. Prucnal, S. Facsko, C. Baumgart, H. Schmidt, M.O. Liedke, L. Rebohle, A. Shalimov, H. Reuther, A. Kanjilal, A. Mucklich, M. Helm, J. Zuk, and W. Skorupa, Nano Lett. 11, Issue 7, 2814-2818 (2011)
[2] S. Prucnal, M. Glaser, A. Lugstein, E. Bertagnolli, M. Stöger-Pollach, S. Zhou, M. Helm, D. Reichel, L. Rebohle, M. Turek, J. Zuk, and W. Skorupa, Nano Res. 7, 1769 (2014)